<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title></title>
    <style>
        .box{
            width: 300px;
            height: 300px;
            /* background-color: red; */
            background: linear-gradient(to center blue red );
        }
    </style>
</head>
<body>
    <div class="box">

    </div>
</body>
</html>